The present invention relates to a procedure for photo engraving in high definition on metal and/or ceramic with metal covering. It is particularly useful for decorating items of metallic or ceramic jewelry and for producing high definition images on porcelain articles such as tableware and presentation pieces.
Procedures are currently known for photographic printing on metals that consist of impregnating the metal with photographic emulsion based on silver nitrates. When exposed to an actinic light a surface photograph is produced without engraving, with low resistance to friction and/or high temperatures.
Other known procedures consist of anodizing portions of aluminum to form a surface layer of absorbent oxide. A sensitizer of sales is later applied that impregnates the pores of this oxide layer. It is later exposed to actinic light and then conventional photographic developing, with a final sealing in water at 98° C.
This procedure allows for variations of chemical components used, with the image made in black or blue. The images obtained are resistant and enduring but are not engraved images. Furthermore, these procedures can only be carried out on aluminum.
Other procedures, such as the offset technique, are used on lithographic plates which have the sensitive emulsion only so that after developing and processing the positive or negative they divide the greasy element from the aqueous element, but do not produce an engraving.
Known techniques of engraving are carried out mechanically or by laser, using engraving machines, but they do not offer good quality or high definition.
When decorating on ceramics and porcelain, the present techniques require transferring of decals, using serigraphy in four colours and then processing them at high temperatures in baking ovens. The definition of the printing is very low.